🍊 Los Angeles — READ & QUERY (CRUD Submodule 2)

Quest Chapter: The Food Route
Focus: R in CRUD — READ & QUERY
Location: Los Angeles, CA 🌆🌮

Welcome to LA! This interactive page teaches database READ operations through LA’s diverse food scene. Master SELECT queries, filtering, pagination, and search techniques.

🎯 Los Angeles Progress Tracker

🍖 Korean BBQ - Incomplete

🌮 Street Tacos (al pastor) - Incomplete

🍔: In-N-Out Burger - Incomplete

🥑 Avocado Toast - Incomplete

🍜 Ramen & Fusion Dishes - Incomplete

🥤 Erewhon - Incomplete

Completion: 0%

Korean BBQ query — +15 XP

🎉 San Francisco Unlocked!
You can now continue to the next city!

🧠 What Does READ Mean?
- In databases, READ = retrieving existing records using SELECT queries.
- On the web, a client sends GET /api/dishes requests with filters.
- The server processes:
  - SELECT statements to fetch data,
  - WHERE clauses to filter results, and
  - ORDER BY, LIMIT for sorting and pagination.
- Analogy: your database is like a restaurant directory. Reading = searching the directory for specific cuisines, prices, or ratings.

🍖 Korean BBQ SELECT Query

Practice SELECT queries to retrieve Korean BBQ dishes from our database. Learn basic data retrieval patterns.

// Korean BBQ - Basic SELECT operations
const koreanBBQQuery = {
  // Basic SELECT query
  getAllKoreanBBQ: () => {
    return `
      SELECT dish_id, name, protein, marinated_hours, grill_temperature, price
      FROM korean_bbq_dishes 
      WHERE cuisine_type = 'Korean BBQ'
      ORDER BY price ASC;
    `;
  },

  // SELECT with specific filters
  getSpicyKoreanBBQ: () => {
    return `
      SELECT name, spice_level, banchan_count, price
      FROM korean_bbq_dishes 
      WHERE spice_level >= 3 
        AND cuisine_type = 'Korean BBQ'
        AND city = 'la'
      ORDER BY spice_level DESC;
    `;
  },

  // SELECT with calculated fields
  getBBQWithTotalCost: () => {
    return `
      SELECT 
        name,
        price,
        (price * 1.09) AS price_with_tax,
        CASE 
          WHEN price < 15 THEN 'Budget'
          WHEN price < 25 THEN 'Mid-range'
          ELSE 'Premium'
        END as price_category
      FROM korean_bbq_dishes
      WHERE cuisine_type = 'Korean BBQ';
    `;
  }
};

// Execute queries and display results
console.log("🍖 Korean BBQ Query Examples:");
console.log("1. All Korean BBQ:", koreanBBQQuery.getAllKoreanBBQ());
console.log("2. Spicy Korean BBQ:", koreanBBQQuery.getSpicyKoreanBBQ());
console.log("3. BBQ with Tax:", koreanBBQQuery.getBBQWithTotalCost());

// Mock execution
const sampleResults = [
  { name: "Galbi Short Ribs", protein: "beef", price: 28.99, spice_level: 2 },
  { name: "Bulgogi", protein: "beef", price: 22.50, spice_level: 1 },
  { name: "Spicy Pork Belly", protein: "pork", price: 24.99, spice_level: 4 }
];

console.log("📊 Sample Korean BBQ Results:", sampleResults);
completeTask('koreanbbq');

🧩 Quick Quiz:

1️⃣ What does ORDER BY price ASC do?

Shows highest prices first
Shows lowest prices first
Filters by price range

🌮 Street Tacos WHERE Filtering

Master WHERE clauses to filter al pastor tacos by location, price, and authenticity ratings.

// Street Tacos (al pastor) - WHERE clause filtering
const tacoQueries = {
  // Filter by location and authenticity
  getAuthenticTacos: () => {
    return `
      SELECT vendor_name, location, authenticity_score, price_per_taco
      FROM street_tacos 
      WHERE taco_type = 'al pastor'
        AND authenticity_score >= 4.5
        AND city = 'la'
        AND has_pineapple = true;
    `;
  },

  // Price range filtering
  getBudgetTacos: () => {
    return `
      SELECT vendor_name, location, price_per_taco, rating
      FROM street_tacos 
      WHERE taco_type = 'al pastor'
        AND price_per_taco BETWEEN 2.00 AND 4.00
        AND rating >= 4.0
      ORDER BY price_per_taco ASC;
    `;
  },

  // Complex filtering with multiple conditions
  getPremiumTacos: () => {
    return `
      SELECT 
        vendor_name, 
        location,
        price_per_taco,
        authenticity_score,
        CASE 
          WHEN authenticity_score >= 4.8 THEN 'Exceptional'
          WHEN authenticity_score >= 4.5 THEN 'Excellent'
          ELSE 'Good'
        END as quality_tier
      FROM street_tacos 
      WHERE taco_type = 'al pastor'
        AND (authenticity_score > 4.5 OR rating > 4.5)
        AND vendor_type IN ('food_truck', 'street_cart')
      ORDER BY authenticity_score DESC;
    `;
  }
};

// Execute the queries
console.log("🌮 Al Pastor Taco Filtering:");
console.log("1. Authentic Tacos:", tacoQueries.getAuthenticTacos());
console.log("2. Budget Tacos:", tacoQueries.getBudgetTacos());
console.log("3. Premium Tacos:", tacoQueries.getPremiumTacos());

// Mock results
const tacoResults = [
  { vendor: "Leo's Taco Truck", location: "Highland Park", price: 3.25, authenticity: 4.8 },
  { vendor: "Mariscos Jalisco", location: "Boyle Heights", price: 3.50, authenticity: 4.9 },
  { vendor: "King Taco", location: "Multiple", price: 2.75, authenticity: 4.2 }
];

console.log("📊 Found", tacoResults.length, "al pastor vendors");
completeTask('streettacos');

🧩 Quick Quiz:

1️⃣ What does BETWEEN 2.00 AND 4.00 filter?

Exactly $2.00 or $4.00
Less than $2.00
Prices from $2.00 to $4.00 inclusive

🍔 In-N-Out Burger Pagination & LIMIT

Learn LIMIT and OFFSET for pagination. Browse In-N-Out menu items across multiple pages.

// In-N-Out Burger - Pagination and LIMIT queries
const inNOutPagination = {
  // Basic pagination
  getMenuPage: (page = 1, itemsPerPage = 5) => {
    const offset = (page - 1) * itemsPerPage;
    return `
      SELECT item_name, category, price, calories, secret_menu
      FROM innout_menu 
      WHERE available = true
      ORDER BY category, price ASC
      LIMIT ${itemsPerPage} OFFSET ${offset};
    `;
  },

  // Top items with LIMIT
  getTopBurgers: (limit = 3) => {
    return `
      SELECT item_name, rating, order_count, price
      FROM innout_menu 
      WHERE category = 'burger'
        AND available = true
      ORDER BY rating DESC, order_count DESC
      LIMIT ${limit};
    `;
  },

  // Secret menu items
  getSecretMenu: () => {
    return `
      SELECT item_name, description, estimated_price, popularity_score
      FROM innout_menu 
      WHERE secret_menu = true
        AND item_name IN ('Animal Style', 'Protein Style', '4x4', 'Flying Dutchman')
      ORDER BY popularity_score DESC;
    `;
  },

  // Count total items for pagination
  getTotalCount: () => {
    return `
      SELECT 
        COUNT(*) as total_items,
        COUNT(CASE WHEN secret_menu = true THEN 1 END) as secret_items,
        COUNT(CASE WHEN category = 'burger' THEN 1 END) as burger_count
      FROM innout_menu 
      WHERE available = true;
    `;
  }
};

// Demonstrate pagination
console.log("🍔 In-N-Out Pagination Examples:");
console.log("Page 1:", inNOutPagination.getMenuPage(1, 5));
console.log("Page 2:", inNOutPagination.getMenuPage(2, 5));
console.log("Top 3 Burgers:", inNOutPagination.getTopBurgers(3));
console.log("Secret Menu:", inNOutPagination.getSecretMenu());

// Mock pagination results
const mockPage1 = [
  { item: "Hamburger", category: "burger", price: 2.65, calories: 390 },
  { item: "Cheeseburger", category: "burger", price: 2.95, calories: 480 },
  { item: "Double-Double", category: "burger", price: 3.85, calories: 670 },
  { item: "French Fries", category: "sides", price: 1.95, calories: 395 },
  { item: "Chocolate Shake", category: "drinks", price: 2.40, calories: 590 }
];

console.log("📖 Page 1 Results:", mockPage1);
console.log("📊 Showing 5 items per page");

completeTask('innout');

🧩 Quick Quiz:

1️⃣ For page 3 with 10 items per page, what should OFFSET be?

20
30
10

🥑 Avocado Toast LIKE Search

Master LIKE and pattern matching to search for avocado-based dishes across LA brunch spots.

// Avocado Toast - LIKE search and pattern matching
const avocadoSearch = {
  // Basic LIKE search
  findAvocadoDishes: () => {
    return `
      SELECT dish_name, restaurant, price, description
      FROM brunch_menu 
      WHERE dish_name ILIKE '%avocado%'
        OR description ILIKE '%avocado%'
        AND city = 'la'
      ORDER BY price ASC;
    `;
  },

  // Advanced pattern matching
  findToastVariations: () => {
    return `
      SELECT 
        dish_name,
        restaurant,
        price,
        toppings,
        bread_type
      FROM brunch_menu 
      WHERE (dish_name ILIKE '%toast%' OR dish_name ILIKE '%bread%')
        AND (toppings ILIKE '%avocado%' OR description ILIKE '%avocado%')
        AND price BETWEEN 8.00 AND 25.00
      ORDER BY restaurant, price;
    `;
  },

  // Search with multiple patterns
  findHealthyOptions: () => {
    return `
      SELECT 
        dish_name,
        restaurant,
        price,
        calories,
        healthy_tags
      FROM brunch_menu 
      WHERE dish_name ILIKE ANY(ARRAY['%avocado%', '%quinoa%', '%kale%', '%superfood%'])
        OR healthy_tags && ARRAY['vegan', 'gluten-free', 'organic']
        AND calories < 600
      ORDER BY calories ASC;
    `;
  },

  // Full-text search simulation
  searchByKeywords: (keywords) => {
    const keywordPattern = keywords.split(' ').map(k => `%${k}%`).join('');
    return `
      SELECT 
        dish_name,
        restaurant,
        price,
        description,
        ts_rank(to_tsvector('english', description), plainto_tsquery('english', '${keywords}')) AS rank
      FROM brunch_menu 
      WHERE to_tsvector('english', description) @@ plainto_tsquery('english', '${keywords}')
        AND city = 'la'
      ORDER BY rank DESC, price ASC;
    `;
  }
};

// Execute searches
console.log("🥑 Avocado Toast Search Patterns:");
console.log("1. Find Avocado Dishes:", avocadoSearch.findAvocadoDishes());
console.log("2. Toast Variations:", avocadoSearch.findToastVariations());
console.log("3. Healthy Options:", avocadoSearch.findHealthyOptions());
console.log("4. Keyword Search:", avocadoSearch.searchByKeywords("avocado sourdough"));

// Mock search results
const searchResults = [
  { dish: "Classic Avocado Toast", restaurant: "République", price: 14.00, description: "Smashed avocado on sourdough" },
  { dish: "Avocado Benedict", restaurant: "Guelaguetza", price: 18.50, description: "Poached eggs over avocado" },
  { dish: "Superfood Bowl", restaurant: "Café Gratitude", price: 16.00, description: "Quinoa, avocado, kale" }
];

console.log("🔍 Search Results:", searchResults);
console.log("📊 Found", searchResults.length, "matching dishes");

completeTask('avocado');

🧩 Quick Quiz:

1️⃣ What does ILIKE '%avocado%' find?

Exactly "avocado"
Any text containing "avocado"
Text starting with "avocado"

🍜 Ramen JOINs & Complex Queries

Practice JOIN operations and complex queries to explore LA's ramen and fusion scene with restaurant ratings.

// Ramen & Fusion Dishes - JOIN operations and complex queries
const ramenQueries = {
  // Basic JOIN between ramen dishes and restaurants
  getRamenWithRestaurants: () => {
    return `
      SELECT 
        r.restaurant_name,
        r.neighborhood,
        r.rating as restaurant_rating,
        d.dish_name,
        d.broth_type,
        d.spice_level,
        d.price,
        d.fusion_style
      FROM restaurants r
      JOIN dishes d ON r.restaurant_id = d.restaurant_id
      WHERE d.category = 'ramen'
        AND r.city = 'la'
        AND r.rating >= 4.0
      ORDER BY r.rating DESC, d.price ASC;
    `;
  },

  // Complex JOIN with aggregates
  getFusionPopularity: () => {
    return `
      SELECT 
        d.fusion_style,
        COUNT(*) as dish_count,
        AVG(d.price) as avg_price,
        AVG(r.rating) as avg_restaurant_rating,
        MAX(d.spice_level) as max_spice
      FROM dishes d
      JOIN restaurants r ON d.restaurant_id = r.restaurant_id
      WHERE d.category IN ('ramen', 'fusion')
        AND r.city = 'la'
        AND d.fusion_style IS NOT NULL
      GROUP BY d.fusion_style
      HAVING COUNT(*) >= 2
      ORDER BY avg_restaurant_rating DESC;
    `;
  },

  // Multi-table JOIN with ingredients
  getRamenIngredients: () => {
    return `
      SELECT 
        r.restaurant_name,
        d.dish_name,
        d.broth_type,
        STRING_AGG(i.ingredient_name, ', ') as toppings,
        COUNT(di.ingredient_id) as topping_count
      FROM restaurants r
      JOIN dishes d ON r.restaurant_id = d.restaurant_id
      JOIN dish_ingredients di ON d.dish_id = di.dish_id
      JOIN ingredients i ON di.ingredient_id = i.ingredient_id
      WHERE d.category = 'ramen'
        AND r.neighborhood IN ('Little Tokyo', 'Sawtelle', 'West LA')
      GROUP BY r.restaurant_name, d.dish_name, d.broth_type
      HAVING COUNT(di.ingredient_id) >= 5
      ORDER BY topping_count DESC;
    `;
  },

  // Subquery for top-rated fusion
  getTopFusionRamen: () => {
    return `
      SELECT 
        r.restaurant_name,
        d.dish_name,
        d.fusion_style,
        d.price,
        r.rating
      FROM restaurants r
      JOIN dishes d ON r.restaurant_id = d.restaurant_id
      WHERE r.rating >= (
        SELECT AVG(rating) + 0.5 
        FROM restaurants 
        WHERE city = 'la'
      )
      AND d.category = 'ramen'
      AND d.fusion_style IS NOT NULL
      ORDER BY r.rating DESC, d.price ASC;
    `;
  }
};

// Execute complex queries
console.log("🍜 Ramen & Fusion Analysis:");
console.log("1. Ramen with Restaurants:", ramenQueries.getRamenWithRestaurants());
console.log("2. Fusion Popularity:", ramenQueries.getFusionPopularity());
console.log("3. Ramen Ingredients:", ramenQueries.getRamenIngredients());
console.log("4. Top Fusion Ramen:", ramenQueries.getTopFusionRamen());

// Mock complex results
const fusionResults = [
  { style: "Korean-Japanese", dish_count: 8, avg_price: 16.50, avg_rating: 4.4 },
  { style: "Mexican-Japanese", dish_count: 5, avg_price: 14.25, avg_rating: 4.2 },
  { style: "Vietnamese-Japanese", dish_count: 6, avg_price: 15.75, avg_rating: 4.3 }
];

console.log("🌐 Fusion Analysis:", fusionResults);
console.log("📊 Korean-Japanese fusion is most popular!");

completeTask('ramen');

🧩 Quick Quiz:

1️⃣ What does GROUP BY fusion_style do?

Sorts by fusion style
Filters fusion styles
Groups rows by fusion style for aggregation

🥤 Erewhon Analytics & Indexing

Learn database indexing and performance optimization through Erewhon's premium smoothie analytics.

Smoothie Name Filter Max Calories Min Price Ingredient Filter

🧩 Quick Quiz:

1️⃣ Why would you create an index on the 'ingredients' column?

To speed up WHERE clauses on ingredients
To save storage space
To enforce data validation

🎉 Module Complete — Los Angeles READ Mastery

Congratulations! You’ve mastered READ operations through LA’s diverse food scene:

🍖 Korean BBQ: Basic SELECT queries and ordering
🌮 Street Tacos: WHERE clause filtering and conditions
🍔 In-N-Out: LIMIT, OFFSET, and pagination
🥑 Avocado Toast: LIKE searches and pattern matching
🍜 Ramen & Fusion: JOIN operations and aggregations
🥤 Erewhon: Performance optimization and indexing

San Francisco — UPDATE module unlocked! 🌉 Continue to learn data modification!

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🍊 Los Angeles — READ & QUERY (CRUD Submodule 2)

🎯 Los Angeles Progress Tracker

🎉 Module Complete — Los Angeles READ Mastery